Metal encased refractory article



C. B. REYNOLDS ETAL METAL ENCASED REFRACTORY ARTICLE 3 Sheets-Sheet 1Original Filed Nov. 15 1957 INVENTORS Charles 8. Reynolds Donaid C.Burma Wolfer M. Eklund A ni 25, 1967 c. B. REYNOLDS ETAL 3,

METAL ENCASED REFRACTORY ARTICLE Original Filed Nov. 15, 1957 sSheets-Sheet INVENTORS Charles S. Reynolds DonaldC. Burklo BY Walier M.Eklund Attorney Aprii 1967 c. B. REYNOLDS ETAL 3,315,430

METAL ENCASED REFRACTORY ARTICLE Original Filed Nov. 15, 1957 3Sheets-Sheet F' i g. 11

9 INVENTORS Charles 8. Re nolds Donald C. Bur lo BY Wolfer M. EklundAfforney United States Patent 4 Claims. 01. 52-599 This application is acontinuation of application S.N. 192,299 filed March 20, 1962, and nowabandoned, sai-d application S.N. 192,299 being a division ofapplication S.N. 696,771 filed November 15, 1957 now Patent No.3,083,453.

This invention relates to metal encased nonacid refractory brick forindustrial furnace linings.

Metal-cased refractory articles have long been known in the constructionof industrial furnaces; and many methods have been proposed and used formaking these articles. However, it has been a difiiculty of the priorart that the refractory brick or block has not been safely held by themetal cases, and sometimes the brick fall out of the cases duringhandling and especially during installation in furnaces, so that thebricks themselves may be broken or often cause serious injury to theworkers. Another disadvantage of the prior art has been that in somemethods of proceeding the case could only be applied as the refractoryarticle was being formed and was not therefore applicable to a burnedbrick.

It is an object of the present invention to provide a metal-casedrefractory article wherein the metal case tightly and securely engagesthe refractory component.

According to this invention, there is provided a unitary refractoryarticle comprising a refractory block and a metal casing disposed aboutthe block, the casing comprising a plate of metal which is locallydeformed to fit into and conform with shallow, discontinuous depressionsof the longitudinal face of the refractory object and securely andtightly engages such refractory. Preferably, the casing is of iron orsteel for most industrial uses, but, if desired, other metal plates canbe employed, for example, nickel or aluminum plate is sometimes useful.The refractory block is provided wth one or more shallow discontinuousdepressions in a side face thereof, and the metal plate is placed on theblock and is then deformed to fit into and conform with suchdepressions.

The invention and its mode of operation are further illustrated by theaccompanying drawings, wherein FIGURE 1 is a perspective view of arefractory block having preformed depressions therein useful in makingup the article according to the present invention;

FIGURE 2 is a perspective view of one embodiment of this inventionshowing one shallow depression in one longitudinal side and a caseapplied thereover;

FIGURE 3 is a perspective view of a plated article according to thepresent invention comprising the refractory block and a U-shaped case;

FIGURE 4 is a perspective view of another article made according to thepresent invention, including two U-shaped plates;

FIGURE 5 is a perspective view of another embodiment of the presentinvention, comprising a refractory block and a U-shaped plate whereofthe side arms cover at least a major portion of a side of the block;

FIGURE 6 is a perspective view of still another and particularlyadvantageous embodiment of the present invention;

FIGURE 7 is a sectional view on the line 7, 7 of FIG- URE 6;

3,3 15,43 ll Patented Apr. 25, 1967 FIGURE 7a is a detailed view of theuse of the metal button as shown in FIGURE 7;

FIGURE 8 is a perspective view of a hanger unit made according to thepresent invention;

FIGURE 9 is a perspective view of a hanger masonry unit composed of twoblocks and metal-plated according to the present invention;

FIGURE 10 is a perspective view of a pair of blocks showing still afurther embodiment of the present invention;

FIGURE 11 is a schematic arrangement for carrying out a process forfabricating the refractory article of the present invention;

FIGURE 12 shows schematically another arrangement for fabricating thearticle of the present invention.

According to the present invention, a refractory block, preferably anonacid or basic refractory, is preformed to the desired shape, andthere is provided in such block during formation at least one shallow,discontinuous depression. Alternatively, the block or brick is formed,for example in a brick press or in any desired manner, and afterhardening, the desired shallow discontinuous depression or depressionsare formed therein by drilling with a suitable drill. For instance, suchdepressions are formed by drilling with a hard drill, such as a tungstencarbide drill about one inch in diameter. Preferably, two or more suchdepressions are provided in a side face, and, if desired, one or more orpreferably two or more such shallow depressions are provided in a pairof side faces; and in this type of structure the shallow depressions arepreferably in opposed faces.

It has been found, according to the invention, that it is possible tokey a plate onto a refractory brick using a shallow depression andthereby to obtain firm adhesion of the plate to the brick duringsubsequent handling. The depressions are discontinuous and shallow inorder to maintain the strength of the brick, and it has been foundlikewise that these discontinuous depressions enable keying of the plateto the brick in such a manner that the plate does not slip or slide orchange positions with respect to the refractory block which it coats orcontains. In general, these depressions do not exceed about A inch indepth, and preferably are from about to one inch in diameter. Thedepressions can be of any desired configuration, such as circular,square, V-shaped, diamond-shaped, hemispherical and the like.

The metal plate which is applied is preferably a U-shaped plate and ismade of any desired metal. The web of the U-shaped metal plate orchannel fits over a first or one longitudinal face of the brick, and theside arms of the plate adjacent the web extend over the two or pair ofside faces of the brick adjacent the first or one longitudinal face ofthe brick. In many embodiments there may be employed two U-shapedcasings, the side arms of which will extend over approximately one-halfa longitudinal face of the brick, as illustrated for instance in FIGURE6. However, in some instances it is more convenient to plate the brickon three sides, namely the foregoing first side face and pair of sidefaces and in such embodiment the side arms of the U-shaped plate mayextend over substantially the entire pair of side faces of the brick.The depressions can be placed toward the central areas of the side face,but it is usually preferred to place them at approximately the terminaledges of the side arms of the plate. From the foregoing it will beappreciated that the shallow depressions in a side face of a pair ofside faces of the brick are of diminutive area and depth compared to thearea of such side face and the thickness of the brick between such pairof side faces, respectively. Other than U-shaped cases are employed, ifdesired.

The invention is applicable in making metal plated single refractoryblocks, and it can also be employed in making hanger units which arecomposed of two refractory blocks placed side by side so as to form acommon hanger receiving socket, as will be further described below. Instill another mode of operation a U-shaped plate or a pair of U-shapedplates are applied to onehalf only of a refractory block, whereby :theremaining half, lengthwise, of the block remains unplated; and in suchembodiments when these blocks are placed in juxtaposition in a furnacewall, the metal plate of the one will complement the metal plate of thenext one, thereby providing only one thickness of :metal betweenadjacent blocks in a wall.

The refractory block component is a formed shape composed of nonacid,that is neutral or basic, refractory material. It is, for example, madeof deadburned magnesite, alumina, periclase, chromite, magnesia-chromeor chrome-magnesia mixes, or of any other desired neutral or basicrefractories; and the mixes are made up, bonded and formed into shape inthe manner known to the art. If desired, the formed shapes are burned,baked or fired prior to application of the metal encasement; but,alternatively, the metal casing can be applied to the unburned orchemically bonded shapes. As stated above, during formation the shapesare provided with the desired number of shallow, discontinuousdepressions in one or more side faces thereof, or, alternatively, thedepressions as desired [are drilled into the formed brick. The ordinarystraight brick or rectangular parallelepiped is shown, for instance, inmost of the figures, but a wedge or key form well known in this art canalternatively be employed as shown in FIG. 4. Also, a composite articleis made up according to one embodiment, comprising two refractoryblocks, disposed on end and side by side and encased in a pair ofU-shaped casings keyed to the brick according to the invention bydeformation of the metal plate into the shallow, discontinuousdepression in the side face of at least one of the bricks; and, ifdesired, a metal spacer or divider plate is disposed between facingsurfaces of the two blocks. This spacer or divider plate is made of anydesired material, but most usually iron or steel is employed.

According to one mode of fabricating the refractory article of thepresent invention, a basic or neutral refractory block is prepared withone or more shallow depressions in one or more of the side faces of theblock,.-as desired. The U-shaped casing is placed on the block in suchmanner that the web engages a first or one longitudinal face, and thepair of side arms extend over the pair of side faces of the brick orblock adjacent the first face thereof, and the terminal edges of theside arms extend over or lie directly above the depressions in theblock. Pressure is now applied to portions of the terminal edges or edgeof the side arms to force the metal thereat into conformity with thedepression in the block, and the case is thus keyed to the block in asafe and secure manner. It is preferable that the terminal edge of aside arm overlie two such depressions and be depressed into conformitywith the depressions in order to obtain more secure affixation of theplate to the block, with less tendency of the plate to be moved orskewed about with reference to the block.

In another mode of carrying out the making of a refractory article ofthis invention, a brick is provided with the shallow depressions asdescribed above, and a U- shaped metal plate is placed on the block insuch manner that the web engages one longitudinal side face and the sidearms extend over and in contact with two adjacent side faces of theblock. Preferably, two shallow depressions underlie at least one of theside arms of the metal plate. The metal plate is now heated directlyabove the shallow depressions and is pressed and deformed intoconformity with the brick while being heated. The heating step increasesthe plasticity of the metal and facilitates its deformation into thedepression. After the metal has been depressed into conformity with thedepression in the brick, heating is continued for a short time torelieve stresses in the metal. It is an advantage of this mode ofoperation that a thicker metal can be employed and can be depressed withgreater ease into the depressions, with less chance of damage to themetal and to the brick. Furthermore, it enables depressing metal intothe shallow depressions at any desired part of the metal case, whereaswhen the metal is deformed into the depressions in the cold and withoutheating, it is preferred to do so at the edges of the U-shaped arms.

In a particularly advantageous mode of operation a brickis provided withthe preformed shallow depressions as previously described, that is withone or more, preferably two, depressions in one or more side faces. Asmall metal piece, such as a metal button of any desired shape whichfits into the depression, is placed therein and then two U-shaped platesare placed on the brick in such manner that the edges of the side armsare disposed above, or approximately abut over, the metal buttons orpieces disposed within the recesses. Suitably, the metal button is apiece of metal, such as iron, steel, nickel or other desired metal, of ashape slightly smaller than but conforming to the shape of thedepression and wholly contained within the depression when placedtherein. If desired, the metal button or piece is held within the recessby a small amount of an adhesive such as a rubbery adhesive, or a glue.After the U-shaped cases are so placed that the edges of the side armsare disposed above the metal piece, welding heat is applied in suchmanner as to weld the cases together by means of the metal button, andsince the metal button is disposed within the brick recess, it anchorsthe cases to the brick very firmly and insures continued tightengagement between the case and the brick. Very good results areobtained according to this mode of operation by providing a brick havingtwo shallow recesses in one side face, placing a metal button in eachsuch shallow depression, placing the two U- shaped cases on the brickwhereby the edges of two side arms are disposed over the shallowdepressions and metal pieces, and welding the cases together through themetal button, the shallow depressions being disposed in a linesubstantially parallel with the longitudinal axis of the brick. Ifdesired, however, one or more such shallow depressions can be disposedin opposing side faces of the brick, whereby they underlie both pairs ofedges of the side arms of the U-shaped cases. In still another method,the edges of the side arms can be depressed into the preformed shallowdepressions in the brick, a small piece of metal laid into thedepression in the metal case and heat, for example, welding heat, isthen applied, whereby the metal becomes plastic and flows or is deformedinto the shallow depression, filling it and keying the case securely tothe brick. Alternatively, two or more L-shaped cases can be applied tothe brick and affixed thereto in this manner, welding by means of metalbuttons placed within the shallow depressions.

The invention will now be described with particular reference to theaccompanying drawings.

FIGURE 1 shows a masonry unit which is a magnesia refractory brick 10having a side face 11 in which are disposed two shallow depressions 12,which is suitable for encasement according to the present invention.

FIGURE 2 shows a basic refractory brick 10 which is provided with ashallow depression 12 in side face 11 thereof, and having U-shaped metalcasing disposed over one side face and extending, about half-way overeach of the two adjacent side faces of the brick, the edge 26 of casing13 passing over depression 12, and being depressed therein and intoconformity with the depression as at 16.

FIGURE 3 is another embodiment of the present invention in which 10 islikewise a basic brick provided with a U-shaped casing 13 coveringsubstantially half of the entire area of the side faces of the brick. Inthis embodiment there are provided two shallow depressions 12 in oneside face of the brick, and the edge of casing 13 is depressed intodepressions 12 as at 16, and in substantial conformity with the shape ofone-half of such depression which underlies the edge of case 13. This isa particularly advantageous embodiment in that the provision of twodepressions in one side face of the brick assists in preventing anytwisting with respect to the brick during subsequent handling.

In FIGURE 4 is shown a brick which is likewise a basic brick but is ofwedge shape. Brick 10' carries two U-shaped casings 13 and 13', theedges of which 26 and 26 lie adjacent each other and over shallowdepressions 12 in brick 10'. Shallow depressions 12 of which there arelikewise two in number, are disposed on the opposing side face of brick10 and the opposing edges of cases 13 and 13' lie adjacent each otherover depressions 12'. According to the present method, the casings 13and 13 are depressed as at 16 and 16' into conformity with the shallowdepressions 12 and 12 in brick 10' and serve to key the casings to thebrick and in secure attachment thereto.

FIGURE 5 shows another embodiment of the present invention in which itis particularly advantageous to deform the metal into conformity withthe shallow depression in the brick with the use of heat. Basic brick 19is provided with U-shaped casing 14 of which the side arms are longenough to substantially cover the entire side 11 of brick 10. Shallowdepressions 12 have been previously provided in the side face 11 bydrilling with a tungsten carbide drill, and heat and pressure areapplied to the metal casing in order to deform the casing at intoconformity with the shallow depressions 12, the heating being continuedto relieve stresses in the metal. Heat, to deform the metal, can beapplied in this manner in a simple fashion with the use of spot weldingmachine having water-cooled copper electrodes about inch in diameter,maintaining the temperature below that which welding would occur.

In FIGURES 6, 7 and 70 there are shown views of a particularlyadvantageous method of encasing bricks as described herein. As anexample, ibasic brick 10 is provided with shallow hemisphericaldepressions 12, preferably two on one side face of the brick as shown inFIGURE 6, and about inch in diameter, and preferably disposed at aboutthe central axis of side face 11 and parallel to a longitudinal axis ofthe brick. Metal pieces or buttons 17 which are suitably smaller thandepressions 12, but the diameters of which are greater than half thediameter of depression 12 so that they will underlie both edges of theU-shaped casings to be applied, are placed in depressions 12. If thebrick is lying on its side so that depressions 12 are in the upper face,no precautions are needed to maintain buttons 17 in place, but,alternatively, they can be affixed in the depressions by a small amountof a suitable adhesive and then forwarded to the casing station. Casings13 and 13', of the ordinary U-shaped type, are then placed on brick 10so that their edges overlie buttons 17. Welding heat is then applied andthe case edges are depressed and are welded together through buttons 17.This embodiment is shown in crosssection in FIG. 7 which is taken online 7, 7' of FIG. 6 and shows in greater detail the disposition of thevarious elements. FIG. 7a is a detail showing the button 17 in adepression 12 of brick 10, and the overlying edges of cases 13 and 13'which are welded together as at 16 and are slightly depressed into thedepression during the welding operation. In any event, the provision ofthe button insures keying of the casing to the brick and insures thatthe casing will remain firmly attached to the brick during subsequenthandling and installation, while at the same time the brick is notweakened by a continuous groove or by a deep insertion into therefractory material itself.

As shown in FIGS. 8 and 9, the invention is also applicable in applyingcases to hanger units for use in refractory furnace roofs or furnaceroofs to be operated at high temperatures. In FIG. 8 a basic refractorybrick 10 is provided with a hanger-receiving or support meansreceivingsocket generally indicated at 24, and is also provided with two U-shapedcases 13 and 13', the edges of which overlie shallow depressions 12 inbrick 10 and are deformed into conformity therewith as indicated at 16.FIG. 9 shows a hanger unit comprising two refractory blocks 18 and 18which are provided with recesses which form a common hanger-receivingsocket, generally indicated at 20, in the manner known to this art. Ametal plate 19 is disposed between the adjoining faces of blocks 18 and18'. Two U-shaped casings 21 and 22 are placed over the combined unitand their terminal edges are disposed over shallow depressions 12provided in block 18. The edges of casings 21 and 22 are, according tothe present invention, then depressed, into shallow depressions 12 asindicated at 16, and serve to key the casing to the brick and to insureits firm adherence thereto during subsequent handling and installation.It will be understood that to secure greater adherence of the casings tothe blocks, metal buttons can be placed in depressions 12 and weldingheat applied in the same manner as described with reference to FIGURE 6.

FIGURE 10 shows still another embodiment in which U-shaped cases 23 and23 are so applied to a brick 10 as to cover substantially one-half ofthe side faces thereof. The metal cases in this embodiment are alsodepressed as at 16 into conformity with a preformed shallow depression12 in brick 10 and are thereby keyed to brick 10. In this embodimentone-half of each brick 10 is metal plated or coated in this manenr andwhen installed in a furnace, they are so juxtaposed as shown in FIG. 10that a single layer of metal lies between each pair of bricks.

FIGURE 11 shows in a schematic form an arrangement for encasing bricksof the present invention. Basic brick 10 is placed on a suitableconveyor with its side face 11 bearing two shallow depressions 12, andcase 13 is placed on brick 10 so that its edge 26 overlies depressions12. The brick and casing then pass to the pressing station wherehydraulic or air pressure is applied by means of rams 25 to deform thecasing as at 16 into conformity with the shape of about one-half ofdepression 12. Where the case is to be heat deformed, there can beemployed the spot-welding device with copper, water-cooled electrodesdescribed above, or ram devices can be employed which are heated, e.g.by electrical resistance, and which can be operated by air, steam orhydraulic pressure. When metal is to be deformed into the depression, itis frequently advantageous to apply heat in order to effect suchdeformation of metal more rapidly and with less strain to the metal. Inthe arrangement of FIG. 11, if a second U-shaped casing is to beapplied, the brick is turned over, another casing applied to theuncoated side and the brick and casing forwarded to the depressingstation as previously described.

FIGURE 12 shows schematically an arrangement for encasing brick of thepresent invention when a metal button is employed. In this arrangementthere is provided a basic refractory brick 10 having depressions 12 inone side face thereof and in the next stage as the brick moves along aconveyor belt of any suitable construction, metal buttons 17 are placedin depressions 12, suitably with the use of a small amount of adhesive(not shown). Then metal casings, of the ordinary U-shape as at 13 and13', are placed on brick 10 in such manner that their edges lie adjacenteach other and are disposed over the metal buttons 17. The bricks andcasings then go to the welding station where two resistant weldingelectrodes are disposed at the same distance apart as depressions 12.The brick 10 and casings 13 are held firmly 'by a backing block 27 whichmaybe maintained under pressure hydraulically or otherwise as indicatedschematically at 28. The welding devices 29 are then moved into contactwith the edges of the metal casings 13 and 13' and metal buttons 17 andwelding heat is applied to weld the casings together while the metal ofthe button 17 melts, joining cases 13 and 13', and after solidification,keying the cases securely to brick 10. Portions of the terminal edges ofcases 13 and 13 will also be slightly depressed into shallow depressions12 under the influence of the heat and pressure of the welding devices.It will be understood that, if desired, casings 13 can be held firmlyagainst the brick during the depressing and/or welding operationsillustrated in FIGURES 11 and 12, by a top pressure block (not shown).

It is an advantage of the present invention that metal casings can beapplied to many shapes of brick with secure affixation to the brick sothat the casings do not fall off during subsequent handling andinstallation, thereby preventing both breakage of the brick and injuriesto workmen. It is a specific advantage that the brick is not weakenedbecause metal does not extend deeply into the brick. The shallowdepressions, which are preferably from about /2 to one inch in diameter,are found to be of sufiicient extent that when metal is pressed downinto conformity with these depressions the casing is effectivelyprevented from springing away from the brick or from moving or slippingabout on the brick, and, furthermore, the depressions assist in handlingthe brick by giving convenient thumb or finger holds to the workmen. Itis a further advantage of the present invention that casings can be moresecurely affixed to a preformed brick which can be either burned orchemically bonded, that is, not burned. In applying metal cases topreformed bricks in the past, it has been proposed to punch a smallportion of the metal into the brick so that a tang of metal extendsdownwardly into the brick material and securely affixes the case to thebrick. However, this often results in zones of weakness or even hairlinecracks which develop into larger cracks upon heating in the furnace andresult in spalling or excessive breakage of the brick; and it is aspecial advantage that the shallow depressions are preformed or drilledinto the brick without production of such zones of weakness or cracks,and the metal which is deformed into such depression exerts sufficientfrictional force to maintain the brick and the casing in secure contact.By means of deformation into the depressions which are shallow anddiscontinuous, the casing is prevented from moving substantially in anydirection.

In the above specific description, where heathas been applied to thecasing, the use of welding devices therefor has been described, but itwill be understood that, alternatively, there can be employed otherlocalized heating, for example, by an oxy-acetylene flame or by otherdesired means. Also, such heating elements, with added pressure means ifnecessary, can be disposed at both sides of the brick if desired todepress metal into the brick on both faces and into one or preferablytwo preformed depressions, as described, in the brick. In heating toeffect deformation or depression of the metal, it has been foundsuitable in practice to heat to cherry red when working with steelplate, but a suitable degree of heat can be readily selected by theoperator. The after-heating to temper, or post-heating, is effected inthe manner well known in the welding art, i.e. at somewhat lesstemperature than the deforming heating and for a short time. Thepreformed depression can be formed in the brick at the time of pressing,and this is an expeditious and economical procedure in general. However,the depressions can also be preformed by drilling or grinding a hole ofthe desired size in the brick after formation, as described above, afterwhich the metal casing is applied as described herein. The casingaffixed to a refractory brick or block according to the presentinvention extends over at least tWo surfaces of such brick and ispreferably a U-shaped, or channel, casing. The adhesive,

which is employed is desired to hold the metal button in place duringforwarding to the welding station, is preferably a combustible adhesivesuch as a sticky, rubbery adhesive of the type of rubber latex,artificial rubber latex, vinyl resin latex or the like, which burns uponheating or firing to form essentially carbon dioxide and water andtherefore does not, upon installation and use in'a furnace,deleteriously affect the strength or other characteristics of therefractory component, even locally, It will be understood that adhesivecan also be applied between the brick and easing, if desired.

Having now described the invention, what is claimed is:

1. Metal encased masonry unit comprising a whole non-acid refractorybrick having a first side face and a pair of side faces adjacent saidfirst side face, one of said pair of side faces having at least onepreformed shallow discontinuous depression free of zones of weakness andcracks and of diminutive depth compared to the thickness of said brickbetween its said pair of side faces, said depression having a surfacelying inwardly of the surface of said one side face, said brick havingits cross-section at said depression not substantially reduced, saiddepression being. of small area compared to the area of said one sideface and lying wholly within a central portion of the latter, a U-shapedmetal casing having a web portion and a pair of side arms adjacent saidweb portion, said casing being firmly adhered to said brick with theinner surface of said web portion in engagement with the surface of saidfirst side face and with the inner surfaces of said pair of side arms inengagement with the surfaces of said pair of side faces, the one sidearm of said metal casing at said one side face having a continuousterminal edge lying over at least a portion of said depression, aprojection extending into said depression formed from the metal of saidone side arm at a portion of said terminal edge overlying saiddepression and of a height not exceeding the depth of saiddepression,said projection having an inner surface in continuous andnon-interrupted relation with the inner surface of said one side arm,said inner surface of said projection conforming substantially to andfrictionally engaging with said surface of said depression to preventrelative movement of said casing and said brick in any direction withrespect to each other, and to retain said inner surface of said web andsaid inner surfaces of said pair of side arms in firm adhering relationwith said surface of said first side face and said surfaces of said pairof side faces of said brick, respectively.

2. Metal encased masonry unit comprising a whole non-acid refractorybrick having first and second side faces and a pair of side facesadjacent said first and second side faces one of said pair of side faceshaving at least one performed shallow discontinuous depression free ofzones of weakness and cracks and of diminutive depth compared to thethickness of said brick between its said pair of side faces, saiddepression having a concave surface lying inwardly of the surface ofsaid one side face, said brick having its cross-section at saiddepression not substantially reduced, said depression being of smallarea compared to the area of said one side face and lying wholly withina central portion of the latter, a pair of U- shaped metal casings eachhaving a web portion and a pair of side arms adjacent said web portion,said U-shaped metal casings being firmly adhered to said brick with theinner surfaces of said web portions in engagement with said first andsecond faces of said brick and with the inner surfaces of said pair ofside arms in engagement with the surfaces of said pair of side faces,the side arms of said metal casing at said one of said pair of sidefaces having continuous terminal edges in opposing relation andoverlying portions of said depression, a projection extending into saiddepression formed from the metal of said last named side arms at aportion of each of said terminal edges overlying said depression and ofa height not exceeding the depth of said depression,

said projections having inner surfaces conforming substantially to andfrictionally engaging with said surface of said depression to preventrelative movement of said casings and said brick in any direction withrespect to each other, and to retain said inner surfaces of said websand said inner surfaces of said pair of side arms in firm adheringrelation with said surfaces of said first and second side faces and saidsurfaces of said pair of side faces of said brick, respectively.

3. Metal encased masonry unit comprising a whole non-acid refractorybrick having first and second side faces and a pair of side facesadjacent said first and second side faces, one of said pair of sidefaces having therein at last on preformed shallow discontinuousdepression free of zones of weakness and cracks and of diminutive depthcompared to the thickness of said brick between its said pair of sidefaces, said depression having a surface lying inwardly of the surface ofsaid one side face, and said depression being of small area compared tothe area of said one side face and lying wholly intermediate the edgesof said one side face a metal button lying within said depression, saidmetal button having an outer surface lying inwardly of the surface ofsaid one side face and an inner surface engaging said surface of saiddepression, a pair of U-shaped metal casings each having a web portionand a pair of side arms adjacent said web portion, said U-shaped metalcasings being mounted on said brick with the web portions thereofoverlying said first and second faces of said brick and with said pairof side arms of each casing extending over and with the inner surfacesof said pair of side arms in engagement with the surfaces of said pairof side faces, the side arms of said metal casings which extend oversaid one of said pair of side faces having continuous terminal edges inopposing relation and overlying portions of said outer surface of saidbutton and said depression, a projection extending into said depressionformed from the metal of said last named side arms at a portion at eachof said terminal edges overlying said depression and said outer surfaceof said button, said projections having inner surfaces in contact withthe outer surface of said button and in continuous and non-interruptedrelation with the inner surfaces of said side arms, said projectionsbeing of a maximum height not exceeding the maximum distance betweensaid outer surface of said button and said one side face, and the innersurfaces of said projections being connected with portions of said outersurface of said button.

4. Metal encased masonry unit comprising a whole non-acid refractorybrick having first and second side faces and a pair of side facesadjacent said first and second side faces, said pair of side faceshaving end edges and side edges, said pair of side faces each having atleast one preformed shallow discontinuous circular depression free ofzones of weakness and cracks and of diminutive depth compared to thethickness of said brick between its pair of side faces, each saiddepression having a concave surface lying inwardly of the surface ofsuch side face, said brick having its cross-section at said depressionsnot substantially reduced, said depressions being of small area comparedto the area of said pair of side faces and disposed intermediate saidend edges and substantially midway of said side edges of said pair ofside faces, a pair of U-shaped metal casings each having a web portionand a pair of side arms adjacent said web portion, said U-shaped metalcasings being firmly adhered to said brick with the inner surfaces ofsaid web portions in engagement with said first and second faces of saidbrick and with the inner surfaces of said pair of side arms inengagement with the surfaces of said pair of side faces, the side armsof said metal casings at said pair of side faces having continuousterminal edges in opposing relation and overlying portions of saiddepressions, projections extending into said depressions formed from themetal of said last named side arms at a portion of each of said terminaledges overlying said depressions and of a height not exceeding the depthof said depressions, said projections having inner surfaces conformingsubstantially to and frictionally engaging with said surfaces of saiddepressions to prevent relative movement of said casings and said brickin any direction with respect to each other, and to retain said innersurfaces of said webs and said inner surfaces of said pair of side armsin firm adhering relation with said surfaces of said first and secondside faces and said surfaces of said pair of side faces of said brick,respectively.

References Cited by the Examiner UNITED STATES PATENTS RE 25,615 7/1964Reynolds et al 52599 X 1,593,297 7/1%6 Gilmer 52311 1,908,414 5/1933Finley 52506 2,034,379 3/1936 Bonsall 5217 2,125,192 7/1938 Morlock 52892,125,193 7/1938 Morlock 52232 2,187,669 1/1940 Stewart 99 2,216,81310/1940 Goldschmidt 52596 2,232,762 2/ 1941 Batcheller 52468 2,480,8048/1949 Yeager et al. 25--1 2,682,703 7/1954 Schob 29235 2,736,187 2/1956Cofiman et al 52599 2,915,893 12/1959 Wilkins 52309 FOREIGN PATENTS522,134 2/1956 Canada. 494,627 10/1938 Great Britain. 567,418 2/1945Great Britain.

FRANK L. ABBOTT, Primary Examiner. JACOB L. NACKENOFF, Examiner. A. C.PERHAM, Assistant Examiner.

1.METAL ENCASED MASONRY UNIT COMPRISING A WHOLE NON-ACID REFRACTORYBRICK HAVING A FIRST SIDE FACE AND A PAIR OF SIDE FACES ADJACENT SAIDFIRST SIDE FACE, ONE OF SAID PAIR OF SIDE FACES HAVING AT LEAST ONEPREFORMED SHALLOW DISCONTINUOUS DEPRESSION FREE OF ZONES OF WEAKNESS ANDCRACKS AND OF DIMINUTIVE DEPTH COMPARED TO THE THICKNESS OF SAID BRICKBETWEEN ITS SAID PAIR OF SIDE FACES, SAID DEPRESSION HAVING A SURFACELYING INWARDLY OF THE SURFACE OF SAID ONE SIDE FACE, SAID BRICK HAVINGITS CROSS-SECTION AT SAID DEPRESSION NOT SUBSTANTIALLY REDUCED, SAIDDEPRESSION BEING OF SMALL AREA COMPARED TO THE AREA OF SAID ONE SIDEFACE AND LYING WHOLLY WITHIN A CENTRAL PORTION OF THE LATTER, A U-SHAPEDMETAL CASING HAVING A WEB PORTION AND A PAIR OF SIDE ARMS ADJACENT SAIDWEB PORTION, SAID CASING BEING FIRMLY ADHERED TO SAID BRICK WITH THEINNER SURFACE OF SAID WEB PORTION IN ENGAGEMENT WITH THE SURFACE OF SAIDFIR SIDE FACE AND WITH THE INNER SURFACES OF SAID PAIR OF SIDE ARMS INENGAGEMENT WITH THE SURFACES OF SAID PAIR OF SIDE FACES, THE ONE SIDEARM OF SAID METAL CASING AT SAID ONE SIDE FACE HAVING A CONTINUOUSTERMINAL EDGE LYING OVER AT LEAST A PORTION OF SAID DEPRESSION, APROJECTION EXTENDING INTO SAID DEPRESSION FORMED FROM THE METAL OF SAIDONE SIDE ARE AT A PORTION OF SAID TERMINAL EDGE OVERLYING SAIDDEPRESSION AND OF A HEIGHT NOT EXCEEDING THE DEPTH OF SAID DEPRESSION,SAID PROJECTION HAVING AN INNER SURFACE IN CONTINUOUS AND NON-INTERRUPEDRELATION WITH THE INNER SURFACE IN CONTINUOUS AND NON-INTERRUPEDRELATION WITH THE INNER SURFACE OF SAID ONE SIDE ARM, SAID INNER SURFACEOF SAID PROJECTION CONFORMING SUBSTANTIALLY TO AND FRICTIONALLY ENGAGINGWITH SAID SURFACE OF SAID DEPRESSION TO PREVENT RELATIVE MOVEMENT OFSAID CASING AND SAID BRICK IN ANY DIRECTION WITH RESPECT TO EACH OTHER,AND TO RETAIN SAID INNER SURFACE OF SAID WEB AND SAID INNER SURFACES OFSAID PAIR OF SIDE ARMS IN FIRM ADHERING RELATION WITH SAID SURFACE OFSAID FIRST SIDE FACE AND SAID SURFACES OF SAID PAIR OF SIDE FACES OFSAID BRICK, RESPECTIVELY.